Water and sewer — Delhi
Delhi Jal Board GPR Survey: Mains, Sewers and Crossings
Locating DJB water mains, sewers and chambers before new pipe work, or before another utility crosses them.
Quick AnswerA Delhi Jal Board GPR survey finds water mains, sewers and chambers, and the other services around them, before new pipe work or a crossing. We use electromagnetic tracing on metal pipes, ground penetrating radar (GPR) on concrete and plastic ones, and manhole measurements for deep sewers. The output becomes part of a wider network record; see smart city underground mapping.
What does a Delhi Jal Board utility survey look for?
A Delhi Jal Board utility survey locates mains, distribution lines, sewers, rising mains and chambers, plus every other service that crosses them. Teams laying new pipe use it to align their work, and other utilities use it to cross DJB assets safely.
The Jal Board was constituted under the Delhi Water Board Act, 1998, and runs drinking water supply and sewerage across most of the capital. Its supply side starts at treatment plants such as Sonia Vihar, Chandrawal, Wazirabad, Haiderpur and Bhagirathi. On the sewer side, house drains feed trunk and interceptor sewers that run to plants such as Okhla.
Two situations bring most enquiries. One is a colony joining the network for the first time, where lanes are already crowded with underground utilities. The other is a fibre, gas or power company that must cross a large DJB main or trunk sewer without touching it.
Can GPR find large and deep pipes?
In most cases yes for mains at normal depth, often not for deep sewers. GPR sees the crown of a large pipe clearly in dry ground, but deep trunk sewers lie beyond its reach, so we locate them from manholes and alignment.
Radar waves travel into the soil and bounce back where buried objects alter its electromagnetic properties; every ground penetrating radar survey rests on that geophysical effect. Moisture and clay shorten the reach. In the Yamuna flood plain the signal fades sooner; on the drier western and southern side it goes further. A large main at one to two metres is an easy target. For a sewer five or six metres down, we open the manholes, measure inverts and draw the line between chambers as inferred.
Unlike metallic pipes, a plastic or concrete line carries no signal. Where one can be entered at a chamber, a small transmitter pushed through it can be traced from the surface. For the full method, see what we do: underground pipeline detection.
Which method suits which pipe?
It depends on the material. Metal pipes carry a tracing signal; concrete and plastic pipes do not, so radar and chamber checks do the work there.
| Pipe material | Common use | Best detection method |
|---|---|---|
| Ductile iron, mild steel, cast iron | Water mains and distribution lines | Electromagnetic tracing, then GPR |
| Prestressed or reinforced concrete | Large water mains, trunk sewers | GPR at shallow depth, manholes for deep lines |
| HDPE and PVC | New distribution lines, sewer laterals | GPR, transmitter tracing where accessible |
| Asbestos cement | Older distribution lines | GPR, records and trial pits |
| Stoneware and brick | Old sewers in older areas | Manhole survey and GPR |
Colony lanes next to municipal roads are surveyed the same way; the MCD utility survey by Mezux Touch page explains the lane approach.
How do you survey a crossing of a DJB main?
With an L-section along the crossing and a short grid either side, so the crossing utility knows the main's position, depth and the clear gap it must keep.
- Find the main at both ends from valves, chambers or records.
- Run GPR passes across it every one to two metres and trace any metal section.
- Mark its centre line and edges on the ground with depth to crown.
- Draw the L-section with the proposed bore or trench and the clearance.
- Note all utility lines in the same strip, since crossings rarely involve one line.
Permission to cross a DJB asset comes from the Board and the road owner; our drawing is the technical part of that file. Soil notes for crossings across the capital are under GPR survey in Delhi details. Lines that continue beyond the city? Then read about GPR survey in Delhi NCR.
How is the data kept useful after the job?
By handing the GPR data over as GIS utility mapping, not only as a PDF. Each pipe gets its material where seen, size where measured, depth, and how confidently we located it.
Supply and sewer networks are repaired constantly, and the same lanes are dug again within a few years. Utility maps that a zonal engineer can open save the next team from starting blind. Every inferred section is marked, and manhole photographs are attached where access allowed. Inside the Lutyens' area, where the council runs its own distribution, our NDMC utility survey team follows the same data format.
What does a DJB-related utility survey cost?
Standard GPR survey is ₹24 per metre and L-section survey is ₹32 per metre, subject to a ₹50,000 minimum order in Delhi NCR. GST is extra.
- A 25 km colony sewer network at the standard rate: ₹6,00,000 plus GST.
- A 2.2 km trunk main alignment with an L-section: 2,200 × ₹32 = ₹70,400 plus GST.
- A single crossing of 60 m: ₹1,920 at the L-section rate, so the ₹50,000 minimum applies; grouping several crossings into one order is better value.
- Whole-order discounts of 25%, 40% and 50% apply above 100 km, 500 km and 1,000 km.
For tender pricing, a sample survey of three or four typical lanes in a 40-colony sewer package shows how many connections and cables each metre of trench will meet. Apply that ratio to the rest of the bid. The same sample drawings can support the first road cutting request while the full survey continues.
Manhole opening with the Board's staff, de-silting or confined-space entry, if needed, is arranged separately.
Invert levels for gravity sewers
A water main can bend around an obstacle; a gravity sewer cannot, because it needs a steady fall between manholes. On DJB sewer work our total station takes cover and invert levels at every chamber, and those figures sit beside the radar depths of crossing pipes and cables. DGPS fixes the first and last manholes to the project benchmark, so the designer can test a new slope against the buried utilities already there. Rising mains and trunk lines get as-built coordinates by the same method. Read about benchmark transfer by DGPS in Delhi and manhole levelling with a total station.
Surveying for DJB and its pipeline contractors
Delhi Jal Board has issued work orders to Mezux Touch itself, and the pipeline contractors, consultants and other utilities on DJB projects bring us in too. Field crews are Mezux employees, the radars and locators belong to the company, and no survey is passed down the line. Each line is identified and mapped by the same team that reports it. For DJB utility mapping, request a site visit for Delhi with the route and the pipe details you have.
Frequently asked questions
Can you find a 1,200 mm water main?
In most cases, at normal depth in dry ground. Large pipes give a strong reflection from the crown.
How do you locate a sewer six metres deep?
From the manholes along it, measuring invert depths and drawing the line between them as inferred.
Do I need permission to cross a DJB pipeline?
Yes, from the Board and the road owner; see details of RoW permission in Delhi NCR for the general process.
Can you work in colonies being connected for the first time?
Yes. Those lanes are often the densest, so we scan at close spacing to detect underground house connections.
Do you cover every DJB zone?
Yes, across Delhi; see our page on survey coverage in New Delhi for the central area.
Is asbestos cement pipe hard to find?
It carries no signal and gives a weaker radar return, so we combine GPR with records and trial pits.
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Written by Saniya Parveen · Technically reviewed by Rahul Rai · Updated 8 November 2026